Hybrid welding-type power source

ABSTRACT

The present invention is directed to a welding-type power source that includes a power source housing and an engine arranged in the power source housing to supply electrical power. An energy storage device is included that is in rechargeable association with the internal combustion engine and arranged to provide welding-type power for at least a given period.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation and claims priority of U.S.patent application Ser. No. 11/163,286, filed on Oct. 13, 2005 now U.S.Pat. No. 7,838,797, which is itself a continuation of U.S. patent Ser.No. 10/709,835, filed Jun. 1, 2004 now U.S. Pat. No. 6,982,398, issuedon Jan. 3, 2006 both entitled “Fuel Saving Engine Driven Welding-TypeDevice and Method of Use” both in the name of Bruce Albrecht.

BACKGROUND OF THE INVENTION

The present invention relates generally to welding-type systems and,more particularly, to a portable welding-type apparatus designed torespond “on-demand” to operator input. The welding-type apparatusincludes an energy storage device capable of providing immediate andsufficient power in conjunction with an internal combustion engine thatcan then be started to compliment the energy storage device and providesufficient operational welding-type power.

Traditional welding-type apparatus can be broken into two basiccategories. The first category receives operational power fromtransmission power receptacles, also known as static power. The secondis portable or self-sufficient, stand alone welders having internalcombustion engines, also known as rotating power. While in many settingsconventional static power driven welders are preferred, engine drivenwelders enable welding-type processes where static power is notavailable. Rotating power driven welders operate by utilizing powergenerated from engine operation. As such, engine driven welders andwelding-type apparatus allow portability and thus fill an importantneed.

Static powered welders initiate the weld process by way of a trigger ona hand-held torch or with an electrically charged stick connected to acharged electrode.

Rotating power driven welders operate similarly, as long as the engineis running. If the engine is shut down, there is typically no residualpower to create an arc. To once again weld, the engine must be startedand run at operational speed to produce the arc. Therefore, it is simplynot possible to manually start and stop the engine between each andevery break in the welding process. Further, even during longer periods,operators may find it easier to let the engine run because of distanceto the engine, a misconception that it is better for the engine, or justout of habit.

However, the welding process is usually not a continuous one. That is,there are many starts and stops involved in welding, and often, othersteps are performed between welding. Such steps can include removingslag, rearranging components, acquiring additional supplies, checkingone's work, or simply taking a break.

Further, rotating power driven welders typically require that the enginebe running at full speed before sufficient power is generated to performthe welding-type process. That is, when initiating the welding-typeprocess, an operator must first start the engine and wait until theengine is at operational speed before beginning the welding-typeprocess. Operational speed is idle for non-welding operation and fulloutput for a welding-type process. This creates long periods of userdowntime, or results in a waste of fossil fuel by leaving the enginerunning. To avoid repeatedly waiting for the engine to reach full state,operators may allow the engine to idle during breaks in the welding-typeprocess. That is, unlike traditional static welders that only use asignificant amount of power during the welding-type process, rotatingpower driven welders can remain running and continually use energy evenduring a break in the welding-type process.

Accordingly, although operation of the engine is not continuallynecessary, operators allow the engine to continuously run. Running theengine at all consumes excess fuel and creates additional noise andexhaust unnecessarily.

As such, although rotating power driven welders provide the requiredpower over a suitable duration, startup and shutdown of the engine andthe delay associated therewith, and the wasted use of energy of allowingthe engine to run continuously, are significant drawbacks to rotatingpower driven welding-type apparatus.

It would therefore be desirable to design a portable welding-type devicethat is operationally equivalent to static welders. Specifically, itwould be desirable to have a portable welding-type device that operateson-demand and meets the power requirements of the desired welding-typeprocess.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to a portable welding-type apparatusthat overcomes the aforementioned drawbacks. Specifically, the presentinvention includes a portable welding-type power source that includesboth an energy storage device configured to supply welding-type powerand an engine driven power source. A controller is included thatswitches between the energy storage device and the engine driven powersource to deliver power to drive a welding-type process in an “ondemand” manner.

In accordance with one aspect of the present invention, a welding-typepower source is disclosed that includes a power source housing and aninternal combustion engine driven power source arranged in the powersource housing to supply electrical power. An energy storage device isincluded that is in rechargeable association with the internalcombustion engine driven power source and arranged to providewelding-type power for at least a given period.

In accordance with another aspect of the present invention, a method ofperforming a welding-type process is disclosed that includes initiatinga welding-type process from an energy storage device and starting afossil fuel driven engine. Upon completion of starting the fossil fuelengine, the method includes switching the welding-type process from theenergy storage device to the fossil fuel driven engine.

According to another aspect of the present invention, a welding-typeapparatus is disclosed that includes a welding-type apparatus housingand an engine driven power source configured to supply electrical powerand arranged substantially within the welding-type apparatus housing. Anenergy storage device is included that is connected to the engine drivenpower source and configured to supply power for a welding-type processalternately with the engine driven power source.

According to another aspect of the invention, a welding-type powersource is disclosed that includes a housing and a generator disposed inthe housing and configured to deliver a welding-type power. An energystorage device is rechargeably connected to the generator and configuredto deliver welding-type power over a given duration.

Various other features, objects and advantages of the present inventionwill be made apparent from the following detailed description and thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings illustrate one preferred embodiment presently contemplatedfor carrying out the invention.

In the drawings:

FIG. 1 is a perspective view of a welding-type apparatus incorporatingthe present invention.

FIG. 2 is a block diagram illustrating some of the components of thewelding-type apparatus shown in FIG. 1 in accordance with one embodimentof the invention.

FIG. 3 is a block diagram illustrating some of the components of thewelding-type apparatus shown in FIG. 1 in accordance with anotherembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The present invention is directed to a welding-type apparatus and, morespecifically, to a portable welding-type power source that includes bothan energy storage device and an engine/generator, each arranged to be aprimary welding-type power source. The present invention also includes acontroller configured to selectively drive a welding-type processbetween the energy storage device and the engine, or combinationthereof.

As one skilled in the art will fully appreciate, the hereinafterdescription of welding devices not only includes welders but alsoincludes any system that requires high power outputs, such as heating,cutting systems, aircraft ground support, and auxiliary power/powerbackup systems.

Aircraft ground power units are utilized to power aircraft when on theground. Larger aircraft tend to utilize ground power units which outputAC power while smaller aircraft tend to utilize ground power units whichoutput DC power, typically at about 28 volts and in the range of severalhundred amps. Ground power units that output DC or AC power may developthe DC power from a 3-phase AC source such as a static or rotatingconverter or a generator. In either case, a transformer, rectifier,and/or inverter arrangement may be used to convert the AC power to thedesired AC or DC output as when generating a welding-type power.

Therefore, the present invention is equivalently applicable with anydevice requiring high power output, including welders, plasma cutters,induction heaters, generators, and the like. Reference to welding power,welding-type power, or welders generally, includes welding, cutting,heating power, aircraft ground support, or auxiliary power generators.Description of a welding apparatus illustrates just one embodiment inwhich the present invention may be implemented. The present invention isequivalently applicable with systems such as cutting, induction heatingsystems, aircraft ground support systems, and power generation systems.

FIG. 1 shows a welding-type device 10. The welding-type device 10includes a housing 12 which encloses the internal components of thewelding device. Optionally, the welding-type device 10 includes aloading eyehook 14 and/or fork recesses 16. The loading eyehook 14 andthe fork recesses 16 facilitate the portability of the welding-typedevice 10. Optionally, the welding-type device 10 could include a handleand/or wheels as a means of device mobility. The housing 12 alsoincludes a plurality of access panels 18, 20. Access panel 18 providesaccess to a top panel 22 of housing 12 while access panel 20 providesaccess to a side panel 24 of housing 12. A similar access panel isavailable on an opposite side. These access panels 18, 20, provideaccess to the internal components of the welding-type device 10including, as will be described, an energy storage device suitable forproviding welding-type power. An end panel 26 includes a louveredopening 28 to allow for air flow through the housing 12.

The housing 12 of the welding-type device 10 also houses an internalcombustion engine. The engine is evidenced by an exhaust port 30 and afuel port 32 that protrude through the housing 12. The exhaust port 30extends above the top panel 22 of the housing 12 and directs exhaustemissions away from the welding-type device 10. The fuel port 32preferably does not extend beyond the top panel 22 or side panel 24.Such a construction protects the fuel port 32 from damage duringtransportation and operation of the welding-type device 10.

Referring to FIG. 2, a block diagram of the components of a welding-typedevice 10, such as that shown in FIG. 1 is shown. Specifically, aplurality of elements forming a power source 34 of the welding-typedevice 10 is shown. Within the power source 34 is an engine 36 connectedto a generator 38. When in operation, the engine 36 drives the generator38 to produce power which is delivered to a detection circuit/powerconditioner 40. The detection circuit/power conditioner 40 is inelectrical communication with an energy storage device 42. The energystorage device 42 is controlled to provide power to a converter 44,which, in turn, delivers the conditioned power to a current detectioncircuit/signal circuit 46. As will be described, a switch 48 is providedthat may be controlled by a switch controller 50 to deliver power fromthe engine 36 and generator 38 to a torch 52 and a workpiece 54 toeffectuate a desired welding-type process, instead of from the energystorage device 42, that is merely charged by the engine 36 and generator38. Therefore, it should be appreciated that together the detectioncircuit/power conditioner 40, current detection circuit/signal circuit46, switch control 50, and switch 48 serve as a controller, designatedgenerally by reference numeral 56.

When the power source 34 is not providing any power to drive awelding-type process, the switch 48 is in the open position and theengine 36 is off, as shown, and the converter 44 prohibits the energystorage device 42 from discharging. When an operator desires to begin awelding-type process, the operator engages the torch 52 which causes anelectrical connection between the energy storage device 42 and the torch52 and workpiece 54. Specifically, the converter 44 provides the powernecessary for the welding-type process to the current detectioncircuit/signal circuit 46 which then delivers the power to the torch 52and workpiece 54. As such, the power necessary to effectuate thewelding-type process is delivered substantially immediately uponinitiation of the torch input by the operator, thereby providingon-demand power for the welding-type process.

As will be described, once the current detection circuit/signal circuit46 senses current drawn from the energy storage device 42, the currentdetection circuit/signal circuit 46 generates a start signal 47 that issent to the engine 36/generator 38 to start the engine 36. Therefore,substantially simultaneously with the converter 44 closing theelectrical connection with the energy storage device 42, a start signal47 is generated and sent by the current detection circuit/signal circuit46 to initiate engine start-up.

While it is contemplated that the energy storage device 42 be configuredto readily deliver a power suitable for the desired welding-typeprocess, in alternate embodiments, it may not be so configured.Preferably, the power delivered from the energy storage device 42 to theconverter 44 is converted by the converter 44 to a power suitable forwelding-type processes. However, it is also contemplated that theconverter 44 can include a boost circuit to increase the voltage fromthe energy storage device to be within a suitable range for a particularwelding-type process.

It is also contemplated that a boost and buck circuit configuration maybe used in conjunction with the energy storage device 42 to deliver apower desired for a particular welding-type process. As such, it shouldbe recognized that numerous configurations may be utilized to configurethe converter 44. That is, the use of a forward converter, resonantconverter, Cuk converter, full-bridge converter, half-bridge converter,AC bridge and the like, are equivalent substitutions.

As stated, substantially simultaneously with the current detectioncircuit/signal circuit 46, a start signal is generated by the currentdetection circuit/signal circuit 46. The start signal is sent from thecurrent detection circuit/signal circuit 46 to the engine 36, whichcauses the engine 36 to begin a start-up process.

Therefore, while the energy storage device 42 is providing operationalpower for the welding-type process, the engine 36 begins a start-upperiod. During this start-up period, the engine 36 starts and whilegetting up to operational speed, the generator 38 is not yetsufficiently driven to generate operational power. During this start-upor initialization period, power is instantaneously supplied by theenergy storage device 42, and the detection circuit/power conditionercircuit 40 operates as a sensor to determine whether the generator 38 isproducing enough power for the welding-type process.

Once the current detection circuit/power conditioner circuit 40determines that the generator is providing a sufficient power, theengine 36 and generator operate in a post-initialization orpost-start-up period and the current detection circuit/power conditionercircuit 40 sends a feedback signal 45 to the converter 44 and the switchcontrol 50 indicating that the engine 36 and generator 38 are operatingsufficiently to deliver power suitable for driving the welding-typeprocess.

Accordingly, the converter 44 opens the electrical connection betweenthe energy storage device 42 and the current detection circuit/signalcircuit 46. Substantially simultaneously with the converter 44 opening,or immediately prior to, the switch control 50 closes the switch 48thereby providing power from the engine 36 to the torch 52. Theelectrical opening performed by the converter 44 and electrical closingof the switch 48 are performed rapidly and substantially simultaneouslysuch that the welding-type process performed between the torch 52 andworkpiece 54 is uninterrupted and unnoticeable to the user because ofthe internal switching. That is, the switching of driving electricalsources occurs such that the operator of the welding-type device 10 isunaware of the switching and the welding-type process occurs unimpeded.

However, if a break in the welding-type process occurs, the currentdetection/signal circuit 46 senses an interruption in the welding-typeprocess and generates a signal that is sent to shutdown the engine 36. Atime delay can be used to prevent frequent start/stops of engine 36 forbrief welding interruptions. Additionally, before shutting down, thedetection circuits 40, 46 ensure that the energy storage device 42 issubstantially recharged. As such, the welder operates more efficiently,and noise and combustion emission generated by the engine 36 arereduced.

Once power is no longer being delivered by the generator 38 and isdetected by the detection circuit/power conditioner 40, the detectioncircuit/power conditioner 40 sends a signal to the switch control 50that causes the switch control 50 to open the switch 48.

After the break in the welding-type process ends and the operatorre-engages the torch 52, the previously described operation isreiterated. That is, operational power is again delivered by the energystorage device 42 while the engine 36 begins the start-up period. Onceengine start-up is complete, an electrical configuration of the powersource 34 is switched to deliver power from the engine 36 and generator38.

In accordance with one embodiment of the invention, the engine 36 andgenerator 38 are configured to deliver more power than necessary todrive the welding-type process. In this case, once the engine 36 isoperating to deliver operational power to drive the welding-typeprocess, the detection circuit/power conditioner 40 may intermittentlygenerate some power for the energy storage device 42 thereby deliveringpower to the energy storage device 42. That is, the detectioncircuit/power conditioner 40 closes an electrical connection to theenergy storage device 42. However, in accordance with a preferredembodiment, raw power from the generator 38 is not delivered directly tothe energy storage device 42. Instead, the detection circuit/powerconditioner 40 includes a conversion circuit configured to condition thepower delivered to the energy storage device to be within a chargingpower range. For example, it is contemplated that the detectioncircuit/power conditioner 40 may include a buck converter, or othersimilar converter, to limit current supplied to the energy storagedevice 42. As such, the energy storage device 42 is preferably rechargedwith a trickle charge whenever the engine 36 is at full operationalspeed.

In accordance with another embodiment of the invention shown in FIG. 2,power is not diverted to the energy storage device 42 while the engine36 is providing power to drive the welding-type process. Rather, uponsensing a break in the welding-type process, the switch control 50 opensthe switch 48 and the detection circuit/power conditioner 40 closes todeliver a charging power to the energy storage device 42. In this case,the engine 36 remains running for a predetermined time after the breakin the welding-type process. As such, the detection circuit/powerconditioner 40 receives power from the generator 38, converts the powerto a suitable charging power, and provides the charging power to theenergy storage device 42 to recharge the energy storage device 42 forthe next operational cycle of the welding-type process.

In accordance with yet another embodiment of the invention shown in FIG.2, start-up of the engine 36 is only initiated once the energy storagedevice 42 is sufficiently depleted. That is, the converter 44 monitorscharacteristics of the power delivered by the energy storage device 42and if a current or voltage characteristic of the power output of theenergy storage device 42 drops below a threshold, the engine 36 enters astart-up period. Once the engine enters a post-start-up period, theelectrical configuration of the power source 34 is switched to drive thewelding-type process from the engine 36 and the energy storage device 42is switched off. Accordingly, the energy storage device 42 isefficiently utilized, and short engine running durations are avoided.Again, it should be appreciated that together the detectioncircuit/power conditioner 40, current detection circuit/signal circuit46, switch control 50, and switch 48 serve to function as a controller,designated generally by reference numeral 56.

Referring now to FIG. 3, a block diagram, in accordance with analternative embodiment of the components of welding-type device 10 ofFIG. 1, is shown. In accordance with this embodiment, the engine 36 andgenerator 38 are connected to the switch control 50 and switch 48. Theswitch 48 is controlled by switch control 50 to limit power deliveryfrom the generator 38 to the energy storage device 42. As such,operational power to drive the welding-type process is always deliveredfrom the energy storage device 42 while the engine 36 and generator 38serve to recharge the energy storage device 42. That is, once theoperator initiates a welding-type process, the converter 44 allows powerto be delivered from the energy storage device 42 to the torch 52, andultimately, the workpiece 54. Power delivery continues from the energystorage device 42 until the welding-type process ceases. The engine 36and generator 38 are only caused to operate should the energy storagedevice 42 be depleted to a predetermined level in order to avoidexcessive operation and starts/stops of the engine 36 and generator 38.As such, the energy storage device 42 serves to provide on-demand powerfor a desired welding-type process and the engine 36 serves to rechargethe energy storage device 42.

In accordance with one embodiment, the engine 36 is caused to initiatestart-up in response to the converter 44 supplying any power to thetorch 52/workpiece 54 and sends a start command signal 47 to the engine36/generator 38. As such, engine start-up begins substantiallysimultaneously with operator initiation of the welding-type process. Inthis case, the engine 36 begins start-up while the energy storage device42 is driving the welding-type process. Once the engine 36 reaches apost-start-up period, the switch control 50 closes the switch 48 and acharging power is delivered to the energy storage device 42. Therefore,the switch control 50 and switch 48 function as a controller 56 designedto deliver charging power to the energy storage device 42 once theengine 36 reaches the post-start-up period. The charging power is withina charging power range for the energy storage device 42. Accordingly, aspower is being drawn from the energy storage device 42 to drive thewelding-type process, the energy storage device 42 is simultaneouslybeing recharged. When the welding-type process ends, the engine 36continues operating for a predetermined period to allow the energystorage device 42 to reach full charge.

In accordance with another embodiment, the engine 36 is caused toinitiate start-up only after a break in the welding-type process isdetected. As such, engine start-up begins shortly after the welding-typeprocess ends. In this case, the engine 36 begins start-up once theenergy storage device 42 is no longer driving the welding-type process.Once the engine 36 reaches a post-start-up period, the switch control 50closes the switch 48 and a charging power within a charging power rangeof the energy storage device 42 is delivered directly from the generatorto the energy storage device 42. The engine 36 is configured to continueoperation until the energy storage device 42 reaches a substantialrecharge state.

In either case, the invention allows on-demand delivery of powernecessary to effectuate a desired welding-type process. Furthermore,these specific configurations allow the size and power generationability of the engine 36 and generator 38 to be smaller than an engineand generator configuration that is otherwise necessary.

Therefore, the above-described system enables on-demand responsivenessfrom a portable welding-type power source. The system generates lessnoise and consumes less fuel than traditional engine driven welding-typepower sources that do not utilize such an energy storage device. It iscontemplated, that the engine and generator may operate at variousfrequencies and speeds, while not affecting the welding or auxiliaryoutput.

It is contemplated that the present invention may be utilized with aplurality of welding-type process. For example, the welding-typeapparatus may operate according to a Metal Inert Gas (MIG) welding-typeprocess, formerly known as Gas Metal Arc Welding-type (GMAW) process, aTungsten Inert Gas (TIG) welding-type process, a Shielded Metal ArcWelding-type (SMAW) process, a plasma-cutting process, induction heatingprocess, aircraft ground power process or other welding-type processes.

Therefore, the present invention includes a welding-type power sourceincludes a power source housing and an internal combustion engine drivenpower source arranged in the power source housing to supply electricalpower. An energy storage device is included that is device inrechargeable association with the internal combustion engine drivenpower source and arranged to provide welding-type power for at least agiven period.

In another embodiment of the present invention, a method of performing awelding-type process is disclosed that includes initiating awelding-type process from an energy storage device and starting a fossilfuel driven engine. Upon completion of starting the fossil fuel drivenengine, the method includes switching the welding-type process from theenergy storage device to the fossil fuel driven engine.

An alternate embodiment of the present invention has a welding-typeapparatus housing and an engine driven power source configured to supplyelectrical power and arranged within the welding-type apparatus housing.An energy storage device is included that is connected to the enginedriven power source and configured to supply power for a welding-typeprocess alternately with the engine driven power source.

A further embodiment of the present invention includes a welding-typepower source is disclosed that includes a housing and a generatordisposed in the housing and configured to deliver a welding-type power.An energy storage device is rechargeably connected to the generator andconfigured to deliver welding-type power over a given duration.

The present invention has been described in terms of the preferredembodiment, and it is recognized that equivalents, alternatives, andmodifications, aside from those expressly stated, are possible andwithin the scope of the appending claims.

What is claimed is:
 1. A welding power source comprising: an enginedriven generator configured to produce electrical power for a weldingoperation; an energy storage device coupled to the engine drivengenerator and charged by the engine driven generator, the energy storagedevice configured to provide electrical power for the welding operation;and a detection circuit coupled to the engine driven generator andconfigured to detect whether the engine driven generator is producingsufficient power for maintaining the welding operation; whereinelectrical power from the engine driven generator and electrical powerfrom the energy storage device are provided to the operation in paralleland at the same time, and wherein the electrical power from the energystorage device is provided for the welding operation when the electricalpower of the engine driven generator is insufficient to provideoperational power.
 2. The power source of claim 1, comprising powerconditioning circuitry coupled to receive electrical power from theengine driven generator and to provide conditioned electrical power tothe energy storage device.
 3. The power source of claim 1, comprising aswitch coupled to the engine driven generator and configured to controlapplication of the electrical power from the engine driven generator tothe welding operation.
 4. The power source of claim 3, wherein theswitch is coupled electrically in parallel with the energy storagedevice.
 5. The power source of claim 1, comprising a converter circuitcoupled to the energy storage device and configured to receiveelectrical power from the energy storage device and to output electricalpower suitable for the welding operation.
 6. The power source of claim1, comprising control circuitry coupled to the engine driven generatorand to the energy storage device, and configured to direct electricalpower from both the engine driven generator and from the energy storagedevice to be provided for the welding operation during at least aportion of the welding operation.
 7. The power source of claim 6,wherein the control circuitry is configured to direct electrical powerfrom only the engine driven generator to the welding operation during atleast a portion of the welding operation.
 8. The power source of claim6, wherein the control circuitry is configured to direct electricalpower from only the energy storage device to the welding operationduring at least a portion of the welding operation.
 9. A welding powersource comprising: an engine driven generator configured to produceelectrical power for a welding operation; an energy storage devicecoupled to the engine driven generator and charged by the engine drivengenerator, the energy storage device configured to provide electricalpower for the welding operation; a detection circuit coupled to theengine driven generator and configured to detect whether the enginedriven generator is producing sufficient power for maintaining thewelding operation; and control circuitry coupled to the engine drivengenerator and to the energy storage device, and configured to directelectrical power from both the engine driven generator and from theenergy storage device at the same time to be provided for the weldingoperation during at least a portion of the welding operation.
 10. Thepower source of claim 9, wherein electrical power from the engine drivengenerator and electrical power from the energy storage device areprovided in parallel.
 11. The power source of claim 9, wherein theelectrical power from the energy storage device is provided for thewelding operation when the electrical power of the engine drivengenerator is insufficient to provide power for maintaining the weldingoperation.
 12. The power source of claim 9, comprising a switch coupledto the engine driven generator and configured to control application ofthe electrical power from the engine driven generator to the weldingoperation.
 13. The power source of claim 12, wherein the switch iscoupled electrically in parallel with the energy storage device.
 14. Awelding power source comprising: an engine driven generator configuredto produce electrical power for a welding operation, the engine andgenerator having a size and generation ability insufficient formaintaining power for the welding operation; an energy storage devicecoupled to the engine driven generator and charged by the engine drivengenerator, the energy storage device configured to provide electricalpower for the welding operation; a detection circuit coupled to theengine driven generator and configured to detect whether the enginedriven generator is producing sufficient power for maintaining thewelding operation; and control circuitry coupled to the engine drivengenerator and to the energy storage device, and configured to directelectrical power from both the engine driven generator and from theenergy storage device at the same time to be provided for the weldingoperation during at least a portion of the welding operation.
 15. Thepower source of claim 14, wherein the control circuitry is configured todirect electrical power from only the engine driven generator to thewelding operation during at least a portion of the welding operation.16. The power source of claim 14, wherein the control circuitry isconfigured to direct electrical power from only the energy storagedevice to the welding operation during at least a portion of the weldingoperation.
 17. The power source of claim 14, comprising a switch coupledto the engine driven generator and configured to control application ofthe electrical power from the engine driven generator to the weldingoperation.
 18. The power source of claim 17, wherein the switch iscoupled electrically in parallel with the energy storage device.